The road to this book -- A framework for the implementation of task-based instruction -- Modelling second language performance: integrating complexity, accuracy, fluency and lexis -- Limited attentional capacity and cognition: two hypotheses regarding second language performance on tasks -- Reflections on theory -- The influence of planning on performance in task-based learning -- Self-reported planning behaviour and second language performance in narrative retelling -- Lexical performance by native and non-native speakers on language-learning tasks -- Reflections on planning research -- Reflections on empirical research -- Tasks and language performance -- Models of speaking and the assessment of second language proficiency -- Reflections on assessment.